基于特征结构相似度的遥感影像融合质量评价指标

在分析现有影像融合评价指标的基础上,根据人眼视觉特性,提出一种基于特征结构相似度的遥感影像融合评价指标.首先从原始影像和融合影像中提取空间特征和光谱特征,然后综合计算空间特征和光谱特征的结构相似度作为评价指标,达到评价影像质量的目的.通过对多种传感器获取的遥感影像进行融合实验,结果表明该客观评价方法与主观评价结果一致,...     

水母雪莲不同器官中铅和镉的含量分析

应用石墨炉原子吸收光谱法分析了水母雪莲不同器官中铅、镉的含量。结果表明水母雪莲各器官铅含量由多到少的顺序是叶〉根〉苞片〉茎〉花萼〉花〉种子,各器官镉含量由多到少顺序是花〉苞片〉根〉茎〉叶〉花萼〉种子。本实验方法简便快速,结果准确可靠。     

青海产6种凤毛菊属植物微量元素分析比较

为了比较青海产6种凤毛菊属植物微量元素的含量,应用火焰原子吸收光谱法分析了青海产6种凤毛菊属植物中微量元素的含量.结果表明,水母雪莲中钙和锰的含量最高分别为8148.58mg/kg和312.55mg/kg,唐古特雪莲中铁和锌的含量最高达5798.98、46.22mg/kg.重齿凤毛菊中铜的含量最高为6.09mg/kg....     

高频电压调制对同步运动的影响

从系统的扰动Hamiltonian出发, 在经典力学框架内小振幅近似下, 把粒子的纵向运动方程化为Mathieu方程, 指出了由于扰动的存在, 准等时同步加速器出现了一系列新的共振线。用摄动法导出了一阶不稳定区的边界曲线和禁带宽度; 指出了当粒子穿越禁带后的振幅与同步加速器的两个不稳定点相位相等时, 系统处于临界状态; 并由此导出了高频电压调制振幅的临界值。In the classical mechanics frame and small amplitude approximation, the longitudinal motion equation of the particle was reduced to the Mathieu equation based on the perturbed Hamiltonian. It was pointed out that there is a series of new resonance lines in quasi isochronous synchrotron by the perturbation. The boundary curve and the stop width for order instability zone one were derived by the method of perturbabtion. Also it was pointed that the system is at the critical point when the phase becomes equal to the phase of the instable point for the synchrotron after it crossed the stop band, and the critical condition of the high frequency voltage modulation was derived.     

Cosmic ray test for a T0 detector

The endcap of time-of-flight (ETOF) detector in BES (Beijing Spectrometer) III is planned to be upgraded by using multi-gap resistive plate chambers (MRPCs) and the designed time resolution of the MRPCs is around 50 ps. Thus a time-zero (T0) detector needs to be built to offer a high quality reference time for the MRPCs beam test. So a T0 detector is built using plastic scintillator tiles (BC420) to couple with four fast phototubes (PMTs, Hamamatsu H6533). The timing properties of the detector is studied by using a cosmic ray test and factors related to the time resolution, such as plastic scintillator size, readout mode and angle effects, are discussed. T0 detector timing resolutions of ～41-62 ps are achieved, which means that the T0 detector can be used in the MRPC beam test.     

Radiation induced inter-device leakage degradation

The evolution of inter-device leakage current with total ionizing dose in transistors in 180 nm generation technologies is studied with an N-type poly-gate field device (PFD) that uses the shallow trench isolation as an effective gate oxide. The overall radiation response of these structures is determined by the trapped charge in the oxide. The impacts of different bias conditions during irradiation on the inter-device leakage current are studied for the first time in this work, which demonstrates that the worst condition is the same as traditional NMOS transistors. Moreover, the two-dimensional technology computer-aided design simulation is used to understand the bias dependence.     

幂零--中心化方法

An nxn complex sign pattern(ray pattern) S is said to be spectrally arbitrary if for every monic nth degree polynomial f(λ) with coefficients from C,there is a complex matrix in the complex sign pattern class(ray pattern class) of S such that its characteristic polynomial is f(λ).We derive the Nilpotent-Centralizer methods for spectrally arbitrary complex sign patterns and ray patterns,respectively.We find that the Nilpotent-Centralizer methods for three kinds of patterns(sign pattern,complex sign pattern,ray pattern) are the same in form.     

分配格和素域生成的半环簇

Let V be the variety generated by two-element distributive lattice B2 and k prime fields Fp1,...,Fpk. That is to say that V = HSP{B2, Fp1,...,Fpk}. It is proved that the variety V is finitely based. Also, the two-element distributive lattice B2 and prime fields Fp1,..., Fpk are, up to isomorphism, the only subdirectly irreducible semirings in V. Some known results are extended and enriched.     

用正电子研究半导体材料GaSb的缺陷

用正电子寿命谱和符合多普勒技术研究了电子辐照过的GaSb样品．揭示出原牛未掺杂GaSb样品中存在单空位型VGa相关缺陷，具有284ps左右的寿命值．电子辐照能使这种缺陷的浓度增大，使平均寿命值从辐照前的265Ps增大到辐照后的268ps．低温符合多普勒展宽实验结果表明退火后的电子辐照过的原生未掺杂GaSb样品中仍然存在反位缺陷Gasb．掺Zn、Te样品的实验也证实电子辐照在GaSb样品中会引入VGa，284 ps类型的缺陷．